I would not suggest deca for a female that is just starting gear. Deca would be a much more advanced compound, say for a girl that is big and competing on the national level. I would start with Var. This will not help her lean out. In fact, most of the time, steroids in general cause some water bloat in females. They just respond differently to them then men. Clen would be a good option for tightening up. Then if she took var, maybe a low dose of T3, around 25mcg. If the diet and training are good, she should make some good progress. No need for PCT for a female but I di like to taper off gear for them.
If she is having joint problems, she should also look into increasing fish oil. I would start with around 4-5g a day, see how this helps, split into a couple meals. If she is dieting hard, on low fats, this may be extra beneficial. Also glucosimine. and keep water intake high